1. Field of the Invention
The present invention relates to an ink supply device for supplying ink to a print head.
2. Description of Related Art
A conventional ink supply device is disclosed in U.S. Pat. No. 4,771,295, which is explained below.
As shown in FIG. 5, an ink absorbing member 32 is arranged inside an ink tank 31 and is made of a porous material or fibers. A supply port 34 for supplying an ink absorbed in the ink absorbing member 32 to an ink jet head 35 is arranged inside the ink tank 31. A filter 33 is mounted on the supply port 34. Moreover, the supply port 34 projects into the ink tank 31. Therefore, the ink absorbing member 32 and the filter 33 firmly contact, and the ink absorbing member 32 adjacent to the filter 33 is compressed. As a result, uniform pressure is applied to the whole filter 33 by the compressed ink absorbing member 32. Thereby, ink in the ink absorbing member 32 flows toward the compressed portion, adjacent to the supply port 34, by capillary action. Moreover, the ink absorbing member 32 firmly contacts with the filter 33 to prevent air bubbles from passing from the ink tank 31 to the ink jet head 35.
However, in the conventional ink supply device, the supply port 34 projects into the ink tank 31. Therefore, the ink in the portion of the ink tank 31 that is lower than the supply port 34 cannot be supplied easily to the ink jet head 35, and the ink cannot be effectively used. Moreover, the construction of the device is complex and the manufacturing cost of the device is high because the supply port projects into the ink tank 31.